Magnetic chuck.



0. S. WALKER.

MAGNETIC CHUCK. APPLICATION FILED JULY 23. |914.

1,222,052. Patented Apr. 10, 1917.

I 11 2 l? I 10 L 12 'v 12 zv 12 9; `10 '14 10 9 z5 I lrvenov fil/fvwm 1I/@ Sia/65@ K zffovneey l tangular space adapted to be filled by UNITED STATES PATENT OFFICE.

OAKLEY S. WALKER, OF WORCESTER. MASSACHUSETTS, ASSIGNQR TO O. S. WALKER CO., OF WORCESTER, MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS.

MAGNETIC CHUCK.

Specification of Letters Patent.

Patented Apr. 10, 1917.

To. all whom t may/concern:

Be it known that I, OAKLEY S. YALKER, a citizen ofthe United States, residing at Vorcester, in the county of vorcester and Commonwealth of Massachusetts, have invented a new and useful Improvement in Magnetic Chucks, of which the following, taken in'connection with the accompanying drawings, is a specification.

The present invention relates to the construction-of a magnetic chuck, the face of which is adapted to support and grip the iron or steel pieces which are to be operated upon by the machine with whichthe chuck is used. The invention consists in the construction and arrangement of parts set forth in detail in the following description and particularly pointed out in the claims annexed thereto.

In the accompanying drawings,

Figure l is a top plan view of a chuck embodying my invention.

F ig. 2 is a vertical sectional view on line 2 2, Fig. l, and

Fig. 3' is a fragmentary 33, Fig. 1.

Like reference characters refer to like parts in the different figures.

Referring to the drawings, 1 indicates a rectangular metallic shell or frame, inclosing between its end and side walls a` recthe pole pieces, coils and cores of the chuck in the manner hereinafter set forth. In the present instance I have shown a construction in which the pole pieces constituting the work holding face of the chuck are disposed parallel to the longest dimension of said frame; it will be clear, however, that that dimension of the frame which is transverse to the said pole pieces can be increased indefinitely and additional pole pieces insertedto till the additional space. whereby a chuck, wholly within the scope of the present invention, having pole pieces disposed parallel to the shortest dimension of the section on line frame, is produced.

ltemplates the formation of lVhatever the disposition of the pole pieces with respectto the longest or shortest dimensions of the frame, the invention conshoulders 3 near the upper edges of two opposite ends or sides Q, 2 of the frame, each shoulder having an upstanding tongue 4 terminating below the level of said edge. Each pole piece 5, preferably consisting of a strip of 'Swedish iron, has each end formed on the under side with a4 transverse groove 6, within which the tongue l is received, and is also provided with a downwardly projecting tongue i', received within the groove 8 formed in the side 9. between the body of said side and the tongue l. lith the upper surfaces of said pole pieces 5 flush with the edges of the sides and ends of the frame, the tongues T preferably extend slightly below the tongues at, as shown in Fig. 3, whereby in the assembled structure hereinafter more fully set forth, said pole pieces 5 constitute tie bars serving to prevent the outward springing of the sides or ends 2 between which they extend.

The several pole pieces 5, herein shown as four in number, although it is elear'that any even number of such pieces may be provided, are disposed side by side in a row, and with their interposed gaps of nonmagnetic metal, hereinafter referred to, entirely till the upper portion of the rectangular space inclosed by the frame 1, thereby forming. entirely by themselves, the work holding face of the chuck.

Adjacent pole pieces of said row are adapted to receive magnetism of opposite polarity, and to this end, said pole pieces are connected in pairs to the opposite poles of magnets or core members 9, underlying the same in the space inclosed by said frame. Each core member 9 takes the form of a bar of Swedish iron, Ushaped in cross section, extending parallel to said pole pieces, and each leg l() of said U-shaped bar is encircled by a coil of wire 1l, all of said coils, in the present instance four in number, being connected in series to a source of electrical supply, not shown. The upper edge of each leg 10 is machined, and the same is drawn into intimate contact with the machined under side of the associated pole piece 5, by means of screw bolts l2 passing completely through said legs and part way into the body of said pole pieces, the heads of said bolts lying within counterborcd re cesses in the under surfaces of the bars 9.

In assembling the parts of the structure, the frame l, with the pole pieces 5 loosely in serted therein, is disposed in an inverted position, with the upper faces of said pole pieces resting on a true plane surface. T gaps between adjacent pole pieces, and be lli) with ysaid flanges to prevent the springing or,

distortion oil' the trarne. 'llhe core members 9, supporting the coils oi' Wirev 1l, are next secured in place, by the screw bolts l), thus providing i'or the sus fension of said nieu-- ,bers and coils from the pole pieces which they energize.

ln order to prevent the access of dust or oil to the interior of the chuck, a plate ifiis secured by bolts to the under side ot the trame l, and constitutes a base or supporting member itor the chuck,1 preferably spaced from the under surfaces ci the menibers 9.

ln practice, it is found desirable to vide the contiguous edges of adjacent pole pieces 5 With interlocking projections and recesses l@ and 1'?, as shown clearly in Fig. l, thereby increasing the actual length of the gaps between. said pieces and bringing said gaps into closer proximity at certain portions of the work holding tace olf the chuck than would be possible if said gaps extended parallel to the sides oi the traine. rllhe consequent overlapping1 by the projections 16 on one pole piece 5 ot the core or leg l0 of the adjacent pole piece makes it necessary to eut away said projections on the under side as shown at 18, Fig. to prevent a magnetic short circuiting of the chuck. By the construction above described, certain classes of small Work can be made to span a plurality o?? gaps, 'thereby increasingthe holdin@A power of the chuck with respect 1 ze i Y i to suon. Work.

ln the construction above described, the

. shell ot' the chuck forms no part of' the magL netic circuit; nor does said shell constitute any portion of the actualwork holding` race of the chuck. Said Work holding 'face is constituted entirely by the'- pole pieces the usual tie bars, formed integral with the shell of the chuck, being eliminated. As a consequence, it is possible to bring the pole pieces closer together, with no intermediate magnetic metal therebetween through which leakage of the lines of magnetic force can take place. rThe holding power of the chuck is evenly ditlused over the entire tace thereof, rather than concentrated in a relatively small number of spots on said tace with dead spaces between said spots.

i. i magnetic chuck comprising a shell,-`

and a plurality ot pole pieces overlapping the Walls of said shell and having interlocking; engagementwith saidshell. y

2. A magnetic chuck comprising' a shell, and a plurality of pole pieces having their ends overlappingand inter-locked with the Walls of said shel. p 1

Zit A magnetic chuck comprising a shell, and a plurality of vpole pieces Supported at their ends upon two opposite vwalls of said shell, said pole pieces interlocking With said Walls and thereby constituting tie bars t'o prevent the 'outward sprin ing of said walls of the shell. A

Il. A magnetic chuck coi larising a shell, and a plurality of pole pieces supported between tivo opposite Walls of said shell and nections with said Wall A 5. A magnetic chuck comprising a plurality of pole pieces constituting a Workholding i'ace, and a plurality of core members suspended from said pole pieces.

6. A magnetic chuck comprising a plurality 'of pole pieces, a plurality of core mehr bers suspended troni said pole pieces, and a plurality of magnetizing coils carried by said core members. v

7. A magnetic chuck comprising a plurality of pole pieces, and a core member common to each adjacent pair'ot pole pieces, each core member comprisingn a bar 5.3- shaped-in cross section, having each side in Contact With one pole piece of said pair.

8. A magnetic chuck comprising a plu rality orP pole pieces, magnetizing means for said pole pieces in ContactA therewith, each pole piece having a portion 'overlying the magnetizing means of the adjacent pole pfece and being out away at said portion to :torni a nonmagnetic gap.

cantar s. unitaria. 

